Second Grade Core Mathematics Vocabulary
1
Centimeter
A metric unit of length equal to 1/100th of a meter. A centimeter is about the
width of a pinky finger. (L A.1, F.1)
2
Cone
A solid figure that has a circular base and comes to a point called
the vertex. (L F.6)
3
Cylinder
A solid figure with two congruent circular bases and one curved
surface. (L F.6)
4
Diagonal
A line segment that connects two corners of a polygon and is not a side of the
polygon. (L D.1)
5
Difference
The result of subtraction. In the subtraction equation, 5 – 2 = 3, 3 is the
difference. (L 1.20)
6
Dollar
The basic unit of U.S. currency. One dollar is equal to four quarters, ten
dimes, twenty nickels, or one hundred pennies. (L 3.14)
7
Equation
A number sentence that shows equality between two quantities. (L 1.2)
Example: 4 + 8 = 6 + 6
8
Even Number
A number is even if you can make groups of 2 and have none left over. (L
2.11)
9
Expanded
Number/Form
10
Foot
11
Fourth
Example: 8 is even
; 0 is also even.
`
(Note to teachers – the Expressions definition works well when thinking about
positive even numbers, but does not extend well to negative even numbers
such as -24. The definition in 5th grade – “Any integer that can be divided
exactly by 2”.)
Numbers written in a form that shows the place value of the digits. (L 6.2)
Two different ways to write expanded numbers are:
254 = 2 hundreds + 5 tens + 4 ones
254 = 200 + 50 + 4
A customary unit used to measure length. (L G.2)
12 inches = 1 foot
One of three equal parts of a whole. (L 7.8)
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Fraction
1. Part of a whole. (L 7.8)
A number written with the bottom part (the denominator) telling
you how many equal parts the whole is divided into, and the top
part (the numerator) telling how many you have.
2. Part of a group.
3. Fair shares
1
1
2
2
3
3
A number written with the bottom part (the denominator) telling you
how many equal parts the group is divided into, and the top part (the
numerator) telling how many of the parts you have.
3 of the circles are unshaded.
4
A number written with the top part (the numerator) telling you
how many wholes are being shared, and the bottom part (the
denominator) telling how many ways the wholes are being
equally shared.
If 3 people are fair sharing 2 sandwiches, each person will get
2 of a sandwich.
3
13
Horizontal
Parallel to the horizon; going straight across. (L 1.18, A.1)
14
Inch
A customary unit of length equal to 1/12 of a foot. (L G.2)
15
Is Greater Than (>)
Having a value that is more than that of another quantity or expression. (L 1.21)
16
Is Less Than (<)
Having a value that is less than that of another quantity or expression. (L 1.21)
17
Length
The measure of how long something is or one dimension of a two-dimensional
figure. (L A.1)
18
Number Sentence
An expression of a relationship between quantities as an equation or an
inequality. (L 1.2)
Examples: 7 + 7 = 8 + 6
14 < 92
56 + 4 > 59
19
Odd number
A number is odd if you can make groups of 2 and have one left over. (L 2.11)
Example: 9 is an odd number
(Note to teachers – the Expressions definition works well when thinking about
positive odd numbers, but does not extend well to negative odd numbers such
as -15. The definition in 5th grade – “Any integer that cannot be divided
exactly by 2”.)
20
Rectangular Prism
A solid figure with six faces that are rectangles. (L F.5)
21
Sphere
Three-dimensional figure with no faces, bases, edges, or vertices. All of its
points are the same distance from a given point called the center. (L F.5)
22
Pyramid
A solid figure with one base and whose other faces are
triangles with a common vertex. A pyramid is named
by the shape of its base. (L F.5)
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Symmetry
•
•
Line symmetry – an object has line symmetry when it can be folded to
make two parts that are mirror images. (Also called reflection or bilateral
symmetry.)
Point symmetry – an object has point symmetry when it can be turned less
than a full turn (360o) and still look the same as it did before the turn. (Also
called rotational symmetry.) (L 7.7)
24
Third
One of three equal parts of a whole. (L 7.8)
25
Value
Numerical worth or amount. (begin using in L 1.10)
26
Vertical
At right angles to the horizon; straight up and down. (L 1.18, A.1)
27
Width
The measure of one side or edge of a figure. (L F.5)
28
Yard
A U.S. Standard unit for measuring length. One yard is equal to three feet,
one yard is equal to thirty-six inches. (L G.2)
CST RELATED VOCABULARY
Value
Digit
Opposite number sentence
Solution
Faces
Tally marks/tally charts
Range
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